Several techniques have been used in the past for the treatment of tissue including diseased tissue, such as cancer, to remove, destroy, or otherwise minimize the growth of the diseased tissue. For example, traditional methods of treating diseased prostate tissue include high intensity focused ultrasound (“HIFU”), radiation, surgery, Brachytherapy, cryoablation, hormonal therapy, and chemotherapy. Described herein are improved apparatus and method for treating tissue with high intensity focused ultrasound.
Although the techniques, methods, and apparatus discussed herein have applicability to the treatment of tissue in general, this discussion will focus primarily on the treatment of prostate tissue including Benign Prostatic Hyperplasia (BPH) and prostatic cancer. However, the disclosed apparatus and methods will find applications in localization and treatment of a wide range of diseases which manifest themselves in a localized or “focal” manner, including cancers of the breast, brain, liver, and kidney. As explained herein, the disclosed apparatus uses an intracavity probe which will be particularly useful for focal diseases which are accessible to a transesophageal, laparoscopic or transvaginal probe. Such diseases include esophageal cancer, cancer in the trachea and urethra, ulcers in the stomach and duodenum, and pancreatic cancer. Moreover, a transvaginal probe according to the present invention will provide a minimally invasive sterilization procedure on an outpatient basis, as well as therapy for fibroids, and endometrial ablation. Additionally, in the case of a transducer with multiple focal lengths, blood vessels may be selectively targeted to effect coagulation and cauterization of internal bleeding.
As used herein the term “HIFU Therapy” is defined as the provision of high intensity focused ultrasound to a portion of tissue at or proximate to a focus of a transducer. It should be understood that the transducer may have multiple foci and that HIFU Therapy is not limited to a single focus transducer, a single transducer type, or a single ultrasound frequency. As used herein the term “HIFU Treatment” is defined as the collection of one or more HIFU Therapies. A HIFU Treatment may be all of the HIFU Therapies administered or to be administered, or it may be a subset of the HIFU Therapies administered or to be administered. As used herein the term “HIFU System” is defined as a system that is at least capable of providing a HIFU Therapy.
Various methods have been used to determine whether the above mentioned treatments are successful. The gold standard test is a biopsy of the tissue. However, other post treatment tests have been used in an attempt to determine the success of the above treatments. In the case of treating prostate tissue for prostate cancer, one such test is the level of prostate-specific antigen (PSA) in the blood at various times subsequent to testing. PSA is a serine protease normally produced in the prostate. However, both of these methods, biopsy and PSA monitoring, are conducted after the HIFU Treatment has been completed, typically many months later, and thus are not helpful in assisting the physician in determining either prior to the HIFU Treatment or during the HIFU Treatment the potential success of the HIFU Treatment.
Further, it is known to treat the whole prostate and to monitor the temperature of the prostate during treatment to determine if the temperature rise is sufficient to cause cell death. One method to monitor the temperature rise is to position a thermocouple in the prostate, but this is an invasive procedure. Another method to monitor temperature rise is to perform the HIFU Treatment while the patient is positioned within an MRI device. The MRI device is used to monitor the temperature rise in the prostate.
A need exists for a more reliable method of determining the success of a HIFU Treatment of a given treatment region. Additionally, a need exists for determining the success of a HIFU Treatment which does not subject the patient to invasive testing methods including biopsy and blood draws. Further, a need exists for a cost-effective, reliable method of determining the success of a HIFU Treatment after the completion of a HIFU Treatment, during a HIFU Treatment and/or prior to the commencement of a HIFU Treatment.
It is known that during the treatment of the prostate air bubbles between the probe and the rectal wall, such as between an acoustic membrane of the probe and the rectal wall, or calcification in the rectal wall may block the propagation of HIFU energy from being adequately delivered to the treatment site. Further, the application of HIFU energy in the presence of such an acoustic obstruction may result in damage to the rectal wall, such as a recto-urethral fistula. Traditionally, the physician is trained to observe multiple reverberations from an ultrasound image as an indication of an acoustic obstruction. A need exists for an automated method of detecting acoustic obstructions proximate to the rectal wall to avoid unwanted damage to the rectal wall.
In an exemplary embodiment of the present invention, a method of providing treatment to a treatment region of tissue is provided. The method comprising the steps of: planning a proposed HIFU Treatment of the treatment region; and determining prior to commencement of the proposed HIFU Treatment whether the proposed HIFU Treatment should be successful in treating the tissue of the treatment region. In an example, the determination of whether the proposed HIFU Treatment should be successful is based at least on an energy density of the energy planned to be deposited into the treatment region. In another example, the step of determining prior to commencement of the proposed HIFU Treatment whether the proposed HIFU Treatment should be successful in treating the tissue of the treatment region, comprises the steps of: calculating an energy density for the proposed HIFU Treatment; comparing the calculated energy density to a reference energy density; indicating that the proposed HIFU Treatment should be successful if the calculated energy density is greater than or equal to the reference energy density; and presenting the proposed HIFU Treatment to a reviewer for review if it is indicated that the proposed HIFU Treatment should be successful. In a further example, the step of planning the proposed HIFU Treatment of the treatment region comprises the steps of: generating a representation of the tissue; indicating a location of the treatment region on the representation of the tissue; and providing a plurality of proposed treatment sites within the treatment region, each of the proposed treatment sites having a proposed amount of energy to be deposited thereto. In one exemplary variation, the step of determining prior to commencement of the proposed HIFU Treatment whether the proposed HIFU Treatment should be successful in treating the tissue of the treatment region, comprises the steps of: calculating an energy density for the proposed HIFU Treatment; comparing the calculated energy density to a reference energy density; indicating that the proposed HIFU Treatment should be successful if the calculated energy density is greater than or equal to the reference energy density; and presenting the proposed HIFU Treatment to a reviewer for review if it is indicated that the proposed HIFU Treatment should be successful.
In another exemplary embodiment of the present invention, a method of determining the success of a given HIFU Treatment of a given treatment region is provided. The method comprising the steps of: providing a HIFU System to administer the given HIFU Treatment, the HIFU System including a transducer configured to provide a HIFU Therapy to a plurality of treatment sites and a controller configured to control the position and operation of the transducer; calculating an energy density for the given HIFU Treatment; comparing the calculated energy density to a reference energy density; and classifying the given HIFU Treatment as a successful HIFU Treatment based on the calculated energy density being greater than or equal to the reference energy density. In an example, the treatment region includes at least two treatment sub-portions, each treatment sub-portion including a subset of the plurality of treatment sites. In another example, the HIFU Treatment is a proposed HIFU Treatment and the step of calculating the energy density for the proposed HIFU Treatment includes the steps of: estimating an amount of energy to be deposited at each of the plurality of treatment sites; summing the amount of energy to be deposited at each of the plurality of treatment sites; and dividing the summed amount of energy to be deposited by one of a volume of the treatment region and a mass of the treatment region. In an exemplary variation, the method further comprises the steps of: preventing the HIFU Treatment from commencing if the calculated energy density is less than the reference energy density; and providing an override option whereby the reviewer may request that the HIFU Treatment commence even though the calculated energy density is less than the reference energy density. In a further example, the HIFU Treatment is a current HIFU Treatment and the step of calculating the energy density for the current HIFU Treatment includes the steps of: estimating an amount of energy deposited at each of the plurality of treatment sites which have received HIFU Therapy; estimating an amount of energy to be deposited at each of the plurality of treatment sites which have yet to receive HIFU Therapy; summing the amount of energy deposited at each of the plurality of treatment sites which have received HIFU Therapy and the amount of energy to be deposited at each of the plurality of treatment sites which have yet to receive HIFU Therapy; and dividing the summed amount of energy by one of a volume of the treatment region and a mass of the treatment region. In an exemplary variation, the method further comprises the step of: preventing the HIFU Treatment from progressing if the calculated energy density is less than the reference energy density; and providing an override option whereby the reviewer may request that the HIFU Treatment progress even though the calculated energy density is less than the reference energy density. In still a further example, the HIFU Treatment is a completed HIFU Treatment and the step of calculating the energy density for the completed HIFU Treatment includes the steps of: estimating an amount of energy deposited at each of the plurality of treatment sites; summing the amount of energy deposited at each of the plurality of treatment sites; and dividing the summed amount of energy deposited by one of a volume of the treatment region and a mass of the treatment region.
In a further exemplary embodiment of the present invention, an apparatus for treating tissue is provided. The apparatus comprising: a transducer which is positionable proximate to the tissue, the transducer being configured to emit ultrasound energy and to sense ultrasound energy; a positioning member coupled to the transducer and configured to position the transducer; and a controller operably coupled to the transducer and to the positioning member. The controller being configured to position the transducer with the positioning member and to operate the transducer in an imaging mode wherein images of the tissue are obtained from ultrasound energy sensed by the transducer and in a therapy mode wherein a plurality of treatment sites are treated with a HIFU Therapy with the transducer. The controller being further configured to plan a HIFU Treatment of a treatment region of the tissue to determine prior to commencement of the HIFU Treatment whether the HIFU Treatment should be successful in treating the tissue of the treatment region based on an energy density of the energy planned to be deposited into the treatment region. In an example, the controller is further configured to monitor the HIFU Treatment as the HIFU Treatment progresses to determine whether the HIFU Treatment should be successful in treating the tissue of the treatment region based on an amount of energy deposited into the treatment region and an amount of energy planned to be deposited in the treatment region. In another example, the apparatus further comprises a display operably coupled to the controller, the controller being configured to present the images of the tissue on the display and to provide a visual cue on the display of whether the planned HIFU Treatment should be successful in treating the tissue based on the amount of energy planned to be deposited into the treatment region and the amount of energy deposited in the treatment region. In a further example, the HIFU Treatment should be successful if the energy density is at least equal to a reference energy density.
In yet a further exemplary embodiment of the present invention, a computer-readable medium is provided. The computer readable medium providing instructions for directing a processor to: receive image information from a transducer; generate at least one image from the received image information; determine a treatment region based on the received image information; plan a HIFU Treatment of at least a portion of the treatment region, the HIFU Treatment including a plurality of treatment sites; calculate an energy density corresponding to the planned HIFU Treatment; provide an indication of whether the planned HIFU Treatment is likely to be successful based on the energy density; and control the transducer to conduct the planned HIFU Treatment. In an example, the instructions further direct the processor to prevent the planned HIFU Treatment from commencing if the planned HIFU Treatment is not likely to be successful based on the energy density. In another example, the instructions further direct the processor to monitor the planned HIFU Treatment as the planned HIFU Treatment progresses and to permit a modification to the planned HIFU Treatment. In an exemplary variation, the instructions further direct the processor to calculate an updated energy density corresponding to the planned HIFU Treatment with the modification and to provide an updated indication of whether the planned HIFU Treatment with the modification is likely to be successful based on the updated energy density. In another exemplary variation, the instructions further direct the processor to prevent a further progression of the planned HIFU Treatment with the modification if the updated energy density does not indicate that the planned HIFU Treatment with the modifications is likely to be successful. In a further example, the planned HIFU Treatment is likely to be successful if the energy density is at least equal to a reference energy density. In still a further example, the energy density is calculated by the steps of: estimating an amount of energy to be deposited at each of the plurality of treatment sites; summing the amount of energy to be deposited at each of the plurality of treatment sites; and dividing the summed amount of energy to be deposited by one of a volume of the treatment region and a mass of the treatment region.
In still a further exemplary embodiment of the present invention, a method of providing treatment to a treatment region of tissue with a HIFU Treatment, the HIFU Treatment including the provision of HIFU Therapy at spaced apart intervals to a plurality of treatment sites within the treatment region, is provided. The method comprising the steps of: driving the HIFU Treatment to generate a focal hyperechoic feature for a given treatment site; and maintaining the HIFU Treatment at a level to maintain the generation of subsequent focal hyperechoic features at subsequent treatment sites. In one example, the method further comprises the step of pausing the HIFU Treatment if a non-focal hyperechoic feature is generated. In an exemplary variation, the method further comprises the step of reducing the total acoustic power for subsequent treatment sites of the HIFU Treatment if a non-focal hyperechoic feature is generated which migrates from the respective focal zone.
In yet another exemplary embodiment of the present invention, a method of providing treatment to a treatment region of tissue with a HIFU Treatment, the HIFU Treatment including the provision of HIFU Therapy at spaced apart intervals to a plurality of treatment sites within the treatment region, is provided. The method comprising the steps of: distinguishing between a focal hyperechoic feature and a non-focal hyperechoic feature; continuing the HIFU Treatment upon the observance of the focal hyperechoic feature; and pausing the HIFU Treatment upon the observance of the non-focal hyperechoic feature. In an example, the step of distinguishing between a focal hyperechoic feature and a non-focal hyperechoic feature includes the steps of: generating a post-treatment image of a first treatment site; comparing a region of interest of the treatment region in the post-treatment image to the region of interest of the treatment region in a pre-treatment image; classifying the region of interest as containing a hyperechoic feature based on the comparison of the region of interest of the treatment region in the post-treatment image and the pre-treatment image; and comparing a location of the region of interest to a location of the treatment site, wherein the hyperechoic feature is classified as a focal hyperechoic feature if the location of the region of interest generally coincides with the location of the treatment site.
In still another exemplary embodiment of the present invention, an apparatus for treating tissue is provided. The apparatus comprising: a probe including an acoustic membrane covering at least a portion of the probe and a transducer positioned behind the acoustic membrane, the transducer being configured to emit ultrasound energy and to sense ultrasound energy; and a controller operably coupled to the transducer, the controller being configured to operate the transducer in an imaging mode wherein at least one image of the tissue is obtained from ultrasound energy sensed by the transducer and in a therapy mode wherein a plurality of treatment sites are treated with a HIFU Therapy with the transducer. The controller being further configured to detect the presence of an acoustic obstruction adjacent the acoustic membrane by detecting a repetitive pattern based on the at least one image of the tissue. In an example, the controller is further configured to prevent operation of the transducer in therapy mode based on a detection of an acoustic obstruction.
In a yet still a further exemplary embodiment of the present invention, a method of treating tissue in a treatment region is provided. The method comprising the steps of: imaging the treatment region with an ultrasound transducer; automatically detecting an acoustic obstruction proximate to the ultrasound transducer; and preventing the commencement of a HIFU Treatment based upon the detection of the acoustic obstruction proximate to the ultrasound transducer. In an example, the step of detecting the acoustic obstruction comprises the steps of: analyzing a portion of an image for a repetitive pattern, and determining the presence of the acoustic obstruction based on the presence of the repetitive pattern in the portion of the image. In an exemplary variation, the transducer is positioned within a probe behind an acoustic membrane of the probe and wherein the step of analyzing a portion of the image for a repetitive pattern comprises the steps of: analyzing a first portion of the image at about a position corresponding to the acoustic membrane and the tissue to determine if a first intensity characteristic associated with the first portion meets or exceeds a first upper threshold; analyzing a second portion of the image at about 1.5 times the position corresponding to the acoustic membrane and the tissue to determine if a second intensity characteristic associated with the second portion is below a first lower threshold; and analyzing a third portion of the image at about twice the position corresponding to the acoustic membrane and the tissue to determine if a third intensity characteristic associated with the third portion meets or exceeds a second upper threshold.
In yet still another exemplary embodiment of the present invention, a method of treating tissue in a treatment region with a HIFU Treatment is provided. The method comprising the steps of: initiating a HIFU Therapy to treat a portion of the tissue with an ultrasound transducer; obtaining an image of the treatment region subsequent to attempting to treat the portion of the tissue with HIFU Therapy; automatically detecting an acoustic obstruction proximate to the ultrasound transducer; pausing the HIFU Treatment. In an example, the step of detecting the acoustic obstruction comprises the steps of: analyzing a portion of an image for a repetitive pattern, and determining the presence of the acoustic obstruction based on the presence of the repetitive pattern in the portion of the image. In an exemplary variation, the transducer is positioned within a probe behind an acoustic membrane of the probe and wherein the step of analyzing a portion of the image for a repetitive pattern comprises the steps of: analyzing a first portion of the image at about a position corresponding to the acoustic membrane and the tissue to determine if a first intensity characteristic associated with the first portion meets or exceeds a first upper threshold; analyzing a second portion of the image at about 1.5 times the position corresponding to the acoustic membrane and the tissue to determine if a second intensity characteristic associated with the second portion is below a first lower threshold; and analyzing a third portion of the image at about twice the position corresponding to the acoustic membrane and the tissue to determine if a third intensity characteristic associated with the third portion meets or exceeds a second upper threshold.
Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiments exemplifying the best mode of carrying out the invention as presently perceived.